Chris,
In #4 above, do I use the RPM when the tachometer reads 60mph or when the GPS says I am actually doing 60mph?
If I do the GPS way, I am at 2300 rpm and I would calculate to a 3.73 gear ration running 33" tires. (3.76 but I rounded down) Is that correct? (33 x 2300)/(60x336)=3.76 or...